At some point before Onix Is On!, Charmander evolved into Charmeleon, and was used against Brock in the Pewter Gym, which he apparently won, as Red states that he and Blue were the only ones to win the Boulder Badge. Charmeleon made another appearance in Sigh for Psyduck, trying to take down Koga of Team Rocket and his Arbok. Quite a while afterwards, during which his only appearance is in Oak's mention of his evolution soon after Saur's own into Ivysaur, he was accidentally traded to Red with the rest of Blue's Pokémon, and though he grew little in power during this time, he picked up on Red's happy-go-lucky attitude (while Red's Pokémon became sharp and hostile), much to Blue's surprise.

The next time he was seen, he had evolved once again, some time before Kalling Kadabra, and served a vital role in the final battle against Team Rocket Executives Koga and Sabrina, melting the former's ice-cold Blizzard room by setting the whole building on fire, and managing to defeat the latter's "Thu-Fi-Zer" with Red's Saur and Green's Blasty. In the Pokémon League, he was used against Red's Venusaur, Saur, where he lost due to Red's Lightning Rod strategy.

In the Gold, Silver & Crystal chapter, Blue lent Red his Charizard so he could make it across the ragged mountains. Red returned Charizard right before the battle with the Masked Man in the Ilex Forest along with Blasty (which Green lent him). He was seen in Blue's possession again at the start of FireRed & LeafGreen chapter. During said chapter, Blue took him to Kimberly where she taught him the ultimate fire attack Blast Burn through much hardship on both him and his rival's part. Then, because Red's Aerodactyl had its wings ripped by Deoxys, meaning he had no means to fly, he was traded to Red again for his Venusaur. For a short while the theme FireRed and LeafGreen is fulfilled (in the Japanese version). He was returned to his owner again shortly after the incident, but Blue was petrified soon afterwards. Once freed over two months later, he helped defeat Guile Hideout's giant, fake Kyogre with the 8 other starters' ultimate attacks.